This invention relates to pulse combustion, and more particularly to hybrid pulse combustion turbine engines.
In a conventional gas turbine engine, combustion occurs in a continuous, near constant pressure (Rankine cycle), mode. Such conventional gas turbine engine combustion is notoriously inefficient and has led to many efforts to improve efficiency.
It has been proposed to apply the more efficient combustion of near constant volume combustion pulse detonation engines (PDEs) to turbine engine combustors. In a generalized PDE, fuel and oxidizer (e.g., oxygen-containing gas such as air) are admitted to an elongate combustion chamber at an upstream inlet end, typically through an inlet valve as a mixture (e.g., of hydrocarbon fuel droplets or vapor in air). Upon introduction of this charge, the valve is closed and an igniter is utilized to detonate the charge (either directly or through a deflagration to detonation transition). A detonation wave propagates toward the outlet at supersonic speed causing substantial combustion of the fuel/air mixture before the mixture can be substantially driven from the outlet. The result of the combustion is to rapidly elevate pressure within the chamber before substantial gas can escape inertially through the outlet. The effect of this inertial confinement is to produce near constant volume combustion. It has also been proposed to use an essentially deflagration combustion in a PDE. U.S. Patent Publication Nos. 20040123582A1 and 20040123583A1 and European Patent Convention publications EP1435447A1 and EP1435440A1 disclose various configurations of pulsed combustion gas turbine engines.